Racemic carbamate compounds of aryl alkyl alcohols have been known to be useful as antiepileptics and as muscle relaxants. It was reported in Toxicol. and Appl. Pharm. 2, 397-402 (1960) that when X and R are all hydrogen atoms in structural formula (I), the compound is effective as an antiepileptic agent. Dicarbamate compounds of 2-methyl-3-propyl-1,3-propanediol has been reported and their pharmacological effects have been described in J. Pharmacol. Exp. Ther., 104, 229 (1952).
In U.S. Pat. No. 3,265,728, racemic carbamate compounds represented by the structural formula (III) with a substituent on the phenyl ring has been disclosed as useful in treating central nervous system disorders. In the structural formula (III), R.sub.7 is carbamate or methylene carbamate, R.sub.8 is alkyl with 1-2 carbons, hydroxyalkyl with 1-2 carbons, hydroxy or hydrogen, R.sub.9 is hydrogen, alkyl with 1-2 carbons and Y is selected from the group consisting of fluorine, chlorine, bromine, iodine, methyl, methoxy, phenyl, nitro or amine groups. ##STR2##
In U.S. Pat. No. 3,131,692, the racemic carbamate compounds represented by the Formula (VI) have been disclosed as agents for improved central nervous system treatment with substantially reduced cholinergic side effects. In structural formula (VI), W represents an aliphatic radical containing less than 4 carbon atoms, wherein R.sub.10 represents an aromatic radical, R.sub.11 represents hydrogen or an alkyl radical containing less than 4 carbon atoms, and Z represents hydrogen or hydroxy or alkoxy and alkyl radicals containing less than 4 carbon atoms or the radical --OC(.dbd.O)B, in which B represents an organic amine radical of the group consisting of heterocyclic, ureido and hydrazino radicals and the radical --N(R.sub.12).sub.2 wherein R.sub.12 represents hydrogen or an alkyl group containing less than 4 carbon atoms. Moreover, at least one Z in the structural formula (VI) represents the radical --OC(.dbd.O)B. ##STR3##
In U.S. Pat. No. 2,884,444, dicarbamate compounds from 2-phenyl-1,3-propanediol have been disclosed, and in U.S. Pat. No. 2,937,119 carbamate compounds such as isopropylmeprobamate have been disclosed.
Some of the carbamate compounds described in the previous paragraphs are currently being used in the treatment of central nervous system disorders. However exploratory research is being conducted to identify new carbamate compounds which are even more effective for use in the treatment of various central nervous system diseases.
It is a general phenomenon common to all bioactive substances that some differences are usually observed for the activities of the enantiomers when a stereogenic center is present in a bioactive molecule. Typically, by resolving a racemate mixture of bioactive compound, one enantiomer shows higher activity than the racemate while a lower activity is observed with the other enantiomer. Still one must not blindly accept the foregoing generality when developing bioactive molecules without first obtaining experimental verification, since, on occation, unexpected results are observed due to the complex nature of biological responses to foreign substances.
It is an object of the present invention to provide optically active novel carbamate compounds for therapeutic use, especially compositions containing such carbamate compounds as the active ingredient, which possess therapeutic activity in treating diseases of the central nervous system.